Question 666873
An object floating freely on a river takes 50 seconds to pass under a bridge that is 100 feet wide. To the nearest tenth of a mile, what is the speed of the river's current in miles per hour?
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100 ft/50sec*3600sec/hr*mile/5280ft
ft and sec cancel out, leaving:
100*3600/50*5280 miles/hr≈1.36 mi/hr
speed of the river's current≈1.36 mi/hr